Charlie Gibson says on the record he has “tremendous respect and fondness” for Diane Sawyer, but insiders say he has trouble concealing his dislike of his ABC colleague.

“Charlie has always given Diane the stink eye. He bad-mouths her openly and often,” said our source.

Gibson, 66, had been pushing ABC News president David Westin to promote George Stephanopoulos, the host of Sunday morning’s “This Week,” as his successor.

“He wanted George to get the job,” said one source at the network. “He was shocked when he learned Diane got it, and he was really angry that she stole his thunder. As soon as she was named, it was all about Diane.”

When it was announced on Sept. 2 that Gibson was retiring after four years in the evening anchor chair, the network could have waited to declare who’d get the job, just as it is waiting now to name Sawyer’s replacement on “Good Morning America.”

It is widely believed that Stephanopoulos will get the “GMA” spot, but Sawyer, 63, “doesn’t want it announced until she is ensconced at ‘World News,’ ” said our source.

“It’s all bull[bleep.] They get along just fine,” said an ABC spokeswoman. “They went to Walter Cronkite’s funeral together. They had lunch last month.”

Reached for comment, Gibson told Page Six: “This notion that there is some kind of enmity that exists between Diane and me is just silly. We worked together for over seven years, side-by-side . . . We laughed together, cried together (particularly during the time after 9/11), and developed a strong mutual bond.

“I have tremendous respect and fondness for Diane. Diane and I have talked a number of times about the transition and what this job entails. We’re having lunch this week to continue the conversation.”

That said, Diane might want to have someone test her food at that lunch, just to be on the safe side.